By means of such measuring cells, for example, the variation over time of the transmission of an eluting liquid is determined in order to obtain a chromatogram. The eluting liquid (below: sample) is led through the flow channel of a flow cell and irradiated with suitable light longitudinally or transversely with respect to the flow direction. The flow channel of the flow cell, through which the sample and the light are led, is usually formed as a thin tube with a diameter in the millimeter and sub-millimeter range.
DE 36 03 905 A1 discloses a through-flow particle analyzer, in which a suspension is examined by shining light in. An objective structure, spaced apart by a layer of dispersion oil, adjoins a flow cell, from which reflected light for evaluation enters the objective structure.
U.S. Pat. No. 7,184,141 B2 describes an optical flow cell, in which a liquid to be examined is conveyed and is transilluminated transversely with respect to the conveying direction, in order to be able to draw conclusions about the liquid by using the evaluation of the emerging light.
An optical measuring cell is further also disclosed by US 2011/0299067 A1.